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Abnormal left ventricular diastolic function in chronic Chagas' disease: an echocardiographic study
Insights
Chronic Chagas' disease commonly causes diastolic dysfunction in the left ventricle, affecting all disease stages. This study highlights diastolic disturbances as a key feature of Chagas' cardiomyopathy.
Area of Science:
- Cardiology
- Infectious Diseases
- Echocardiography
Background:
- Chronic Chagas' disease, caused by *Trypanosoma cruzi*, can lead to cardiomyopathy.
- Left ventricular dysfunction is a known complication, but diastolic function patterns require further elucidation.
Purpose of the Study:
- To investigate systolic and diastolic left ventricular function in patients with chronic Chagas' disease.
- To compare echocardiographic and phonocardiographic data with normal controls.
Main Methods:
- Simultaneous M-mode echocardiograms and phonocardiograms were recorded in 19 patients.
- Data were digitized and analyzed to assess left ventricular dimensions, shortening fraction, and velocity of circumferential fiber shortening.
- Isovolumic relaxation time and rate of dimension increase were evaluated for diastolic function.
Main Results:
- Systolic abnormalities included increased left ventricular dimensions and reduced shortening fraction in some patients.
- Diastolic abnormalities were prevalent, with prolonged isovolumic relaxation time (9 patients) and reduced rate of dimension increase (11 patients).
- No asynchronous wall motion during relaxation was observed, distinguishing it from coronary artery disease.
Conclusions:
- Diastolic disturbances are common in all stages of chronic Chagas' disease.
- These diastolic abnormalities may be a fundamental aspect of left ventricular pathology in Chagas' disease.
- Findings emphasize the importance of assessing diastolic function in Chagas' cardiomyopathy.
Abstract:
Simultaneous M-mode echocardiograms and phonocardiograms were recorded in 19 patients with chronic Chagas' disease, and were digitised and compared with normal in order to study systolic and diastolic left ventricular function. Five of the patients were in New York Heart Association class 1, 9 in class 2, and 5 in class 3. Left ventricular cavity dimensions were increased in 3 and shortening fraction reduced in 1. Peak velocity of circumferential fibre shortening was below the 95% confidence limit of normal in 9. In contrast to previous echocardiographic studies, diastolic abnormalities were common, with prolongation of isovolumic relaxation time in 9 patients and reduced rate of dimension increase in 11. However, in spite of regional disease, documented angiographically in 5 of 6 patients, there was no evidence of asynchronous wall motion during relaxation seen in patients with coronary artery disease and comparable segmental abnormalities of wall motion. The relative timing of aortic valve closure and minimum cavity dimension was normal in all but 3 patients, and a significant dimension change during isovolumic relaxation in only one. Thus diastolic disturbances are common at all stages of Chagas' disease, and may represent a fundamental aspect of the pathological process as it affects the left ventricle.